// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_ACCESSIBLE_PANE_VIEW_H_
#define UI_VIEWS_ACCESSIBLE_PANE_VIEW_H_

#include "base/containers/hash_tables.h"
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "ui/base/accelerators/accelerator.h"
#include "ui/views/focus/focus_manager.h"
#include "ui/views/view.h"

namespace views {
class FocusSearch;

// This class provides keyboard access to any view that extends it, typically
// a toolbar.  The user sets focus to a control in this view by pressing
// F6 to traverse all panes, or by pressing a shortcut that jumps directly
// to this pane.
class VIEWS_EXPORT AccessiblePaneView : public View,
                                        public FocusChangeListener,
                                        public FocusTraversable {
public:
    AccessiblePaneView();
    ~AccessiblePaneView() override;

    // Set focus to the pane with complete keyboard access.
    // Focus will be restored to the last focused view if the user escapes.
    // If |initial_focus| is not NULL, that control will get
    // the initial focus, if it's enabled and focusable. Returns true if
    // the pane was able to receive focus.
    virtual bool SetPaneFocus(View* initial_focus);

    // Set focus to the pane with complete keyboard access, with the
    // focus initially set to the default child. Focus will be restored
    // to the last focused view if the user escapes.
    // Returns true if the pane was able to receive focus.
    virtual bool SetPaneFocusAndFocusDefault();

    // Overridden from View:
    FocusTraversable* GetPaneFocusTraversable() override;
    bool AcceleratorPressed(const ui::Accelerator& accelerator) override;
    void SetVisible(bool flag) override;
    void GetAccessibleState(ui::AXViewState* state) override;
    void RequestFocus() override;

    // Overridden from FocusChangeListener:
    void OnWillChangeFocus(View* focused_before, View* focused_now) override;
    void OnDidChangeFocus(View* focused_before, View* focused_now) override;

    // Overridden from FocusTraversable:
    FocusSearch* GetFocusSearch() override;
    FocusTraversable* GetFocusTraversableParent() override;
    View* GetFocusTraversableParentView() override;

    // For testing only.
    const ui::Accelerator& home_key() const { return home_key_; }
    const ui::Accelerator& end_key() const { return end_key_; }
    const ui::Accelerator& escape_key() const { return escape_key_; }
    const ui::Accelerator& left_key() const { return left_key_; }
    const ui::Accelerator& right_key() const { return right_key_; }

protected:
    // A subclass can override this to provide a default focusable child
    // other than the first focusable child.
    virtual View* GetDefaultFocusableChild();

    // Returns the parent of |v|. Subclasses can override this if
    // they need custom focus search behavior.
    virtual View* GetParentForFocusSearch(View* v);

    // Returns true if |v| is contained within the hierarchy rooted at |root|
    // for the purpose of focus searching. Subclasses can override this if
    // they need custom focus search behavior.
    virtual bool ContainsForFocusSearch(View* root, const View* v);

    // Remove pane focus.
    virtual void RemovePaneFocus();

    View* GetFirstFocusableChild();
    View* GetLastFocusableChild();

    FocusManager* focus_manager() const { return focus_manager_; }

    // When finishing navigation by pressing ESC, it is allowed to surrender the
    // focus to another window if if |allow| is set and no previous view can be
    // found.
    void set_allow_deactivate_on_esc(bool allow)
    {
        allow_deactivate_on_esc_ = allow;
    }

private:
    bool pane_has_focus_;

    // If true, the panel should be de-activated upon escape when no active view
    // is known where to return to.
    bool allow_deactivate_on_esc_;

    // Save the focus manager rather than calling GetFocusManager(),
    // so that we can remove focus listeners in the destructor.
    FocusManager* focus_manager_;

    // Our custom focus search implementation that traps focus in this
    // pane and traverses all views that are focusable for accessibility,
    // not just those that are normally focusable.
    scoped_ptr<FocusSearch> focus_search_;

    // Registered accelerators
    ui::Accelerator home_key_;
    ui::Accelerator end_key_;
    ui::Accelerator escape_key_;
    ui::Accelerator left_key_;
    ui::Accelerator right_key_;

    // View storage id for the last focused view that's not within this pane.
    int last_focused_view_storage_id_;

    friend class AccessiblePaneViewFocusSearch;

    base::WeakPtrFactory<AccessiblePaneView> method_factory_;

    DISALLOW_COPY_AND_ASSIGN(AccessiblePaneView);
};

} // namespace views

#endif // UI_VIEWS_ACCESSIBLE_PANE_VIEW_H_
